Re: [PATCH v9 02/14] swiotlb: Refactor swiotlb_create_debugfs

[Christoph Hellwig]

On Fri, Jun 11, 2021 at 11:26:47PM +0800, Claire Chang wrote:
> Split the debugfs creation to make the code reusable for supporting
> different bounce buffer pools, e.g. restricted DMA pool.
> 
> Signed-off-by: Claire Chang 
> ---
>  kernel/dma/swiotlb.c | 23 ---
>  1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
> index 1a1208c81e85..8a3e2b3b246d 100644
> --- a/kernel/dma/swiotlb.c
> +++ b/kernel/dma/swiotlb.c
> @@ -64,6 +64,9 @@
>  enum swiotlb_force swiotlb_force;
>  
>  struct io_tlb_mem *io_tlb_default_mem;
> +#ifdef CONFIG_DEBUG_FS
> +static struct dentry *debugfs_dir;
> +#endif

What about moving this declaration into the main CONFIG_DEBUG_FS block
near the functions using it?

Otherwise looks good:

Reviewed-by: Christoph Hellwig 

[PATCH v9 02/14] swiotlb: Refactor swiotlb_create_debugfs

[Claire Chang]

Split the debugfs creation to make the code reusable for supporting
different bounce buffer pools, e.g. restricted DMA pool.

Signed-off-by: Claire Chang 
---
 kernel/dma/swiotlb.c | 23 ---
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1a1208c81e85..8a3e2b3b246d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -64,6 +64,9 @@
 enum swiotlb_force swiotlb_force;
 
 struct io_tlb_mem *io_tlb_default_mem;
+#ifdef CONFIG_DEBUG_FS
+static struct dentry *debugfs_dir;
+#endif
 
 /*
  * Max segment that we can provide which (if pages are contingous) will
@@ -664,18 +667,24 @@ EXPORT_SYMBOL_GPL(is_swiotlb_active);
 
 #ifdef CONFIG_DEBUG_FS
 
-static int __init swiotlb_create_debugfs(void)
+static void swiotlb_create_debugfs_files(struct io_tlb_mem *mem)
 {
-   struct io_tlb_mem *mem = io_tlb_default_mem;
-
-   if (!mem)
-   return 0;
-   mem->debugfs = debugfs_create_dir("swiotlb", NULL);
debugfs_create_ulong("io_tlb_nslabs", 0400, mem->debugfs, &mem->nslabs);
debugfs_create_ulong("io_tlb_used", 0400, mem->debugfs, &mem->used);
+}
+
+static int __init swiotlb_create_default_debugfs(void)
+{
+   struct io_tlb_mem *mem = io_tlb_default_mem;
+
+   debugfs_dir = debugfs_create_dir("swiotlb", NULL);
+   if (mem) {
+   mem->debugfs = debugfs_dir;
+   swiotlb_create_debugfs_files(mem);
+   }
return 0;
 }
 
-late_initcall(swiotlb_create_debugfs);
+late_initcall(swiotlb_create_default_debugfs);
 
 #endif
-- 
2.32.0.272.g935e593368-goog